What is the reason for no reminder when the passenger seat does not fasten the seat belt?
3 Answers
There are several reasons why there is no reminder when the passenger seat does not fasten the seat belt: faulty seat pressure sensor, internal wiring issues in the seat, or a damaged seat belt power socket. Faulty seat pressure sensor: A malfunctioning seat pressure sensor can cause the vehicle's computer to mistakenly assume there is no passenger in the seat, preventing the seat belt warning from being triggered. A technician can use a specialized automotive diagnostic tool to read the data from the seat pressure sensor and determine if there is a fault. Internal wiring issues in the seat: Poor connection in the seat pressure sensor circuit can prevent the sensor's data signal from being transmitted to the vehicle's computer, making it unable to confirm whether there is a passenger in the seat. A technician can remove the seat cover and use a multimeter to check for faults in the pressure sensor circuit. Damaged seat belt power socket: If the seat belt's power socket is damaged, it cannot transmit the correct signal to the vehicle's computer, leading the computer to mistakenly assume the seat belt is fastened and thus not triggering an alert. A technician can remove the seat belt socket and measure its resistance with a multimeter. If the resistance value is outside the normal range, the fault can be confirmed.
I've encountered this situation before and figured it out myself. When the passenger seat doesn't alert for seatbelt usage, it's usually due to a few common issues. The pressure sensor under the seat might be covered by something, like a thick cushion or clutter pressing on it, preventing it from detecting someone sitting there. Another possibility is poor contact with the metal terminals inside the seatbelt buckle - dust accumulation or rust can develop over time. There's also a chance the connector has come loose, as prolonged vehicle vibration can loosen the wiring connectors under the seat. By the way, if you've previously modified the seat or installed full-coverage floor mats, they might be pressing on the sensor wires. When troubleshooting, I first remove any seat cushions, check the buckle for foreign objects, and finally lift the seat to inspect the connectors. Usually, addressing these areas solves the problem.
My friend's car had the same issue before, and I accompanied him to the repair shop. The mechanic said to mainly check three aspects: failure of the seat pressure sensor (located under the seat cushion, which may malfunction due to moisture or aging); damage to the seat belt buckle switch (the small mechanism inside that detects insertion might be broken); and wiring issues, such as damaged harnesses or oxidized connectors from the seat to the car's computer. During the repair, the mechanic used a computer to read the fault code, which indicated abnormal sensor voltage, and replacing it with a new one fixed the problem. It's recommended not to tamper with the circuit yourself in such cases, as some vehicles require resetting system parameters.
